76. Construct UART Data Frame with Parity Bit

#include <stdio.h>
#include <stdint.h>

typedef struct {
    uint8_t parity_enable : 1;
    uint8_t parity_type   : 1;
    uint8_t reserved      : 6;
} UART_Control;

uint8_t create_uart_frame(uint8_t data, UART_Control *ctrl) {
    if (ctrl->parity_enable == 0) {
        return data &0x7F;
    }
    int ones = 0;
    uint8_t temp = data;
    for (int i = 0; i < 7; i++) {
        if ((temp>>i)&1) {
            ones++;
        }
    }
    uint8_t parity_bit = 0;
    if (ctrl->parity_type == 0) { // Even Parity
        parity_bit = (ones % 2 != 0) ? 1 : 0;
    } else { // Odd Parity
        parity_bit = (ones % 2 == 0) ? 1 : 0;
    }

    // Shift parity to bit 7 and mask data to 7 bits
    return (parity_bit << 7) | (data & 0x7F);
}

int main() {
    uint8_t data;
    scanf("%hhu", &data);  // 7-bit input

    uint8_t parity_enable, parity_type;
    scanf("%hhu %hhu", &parity_enable, &parity_type);

    UART_Control ctrl;
    ctrl.parity_enable = parity_enable;
    ctrl.parity_type = parity_type;

    uint8_t frame = create_uart_frame(data, &ctrl);
    printf("frame = 0x%02X", frame);

    return 0;
}